1Field of the Invention
The present invention relates to a display drive apparatus, and a display apparatus and display drive method thereof, and more particularly to a display drive apparatus for driving a display panel dealing with an active matrix type drive method, a display apparatus equipped with the display drive apparatus, and a display drive method thereof.
2Related Art
In recent years, a display apparatus (emission element type display apparatus), equipped with a liquid crystal display device (LCD) or a display panel in which self-emission elements, such as organic electroluminescence elements (organic EL elements), are two-dimensionally arranged, has been widely applied as a monitor or display of a personal computer and video equipment, and as a display device of portable equipment (mobile equipment), such as a portable telephone, a digital audio player, a digital camera, and an electric dictionary.
In particular, an emission element type display apparatus, to which an active matrix type drive method is applied, has such prominent display characteristics as a display response speed is faster and view angle dependency is also smaller in comparison with those of a liquid crystal display device, and the emission element type display apparatus has a feature in the construction thereof that does not require any back lights and light guide plate unlike the liquid crystal display device. Accordingly, the emission element type display apparatus is expected to be applied to various pieces of electronic equipment in the future as the next generation display device.
Generally, the drive control method of an active matrix type display apparatus, such as a liquid crystal display device and an emission element type display apparatus, performs gradation control on the basis of a voltage component held in each display pixel by setting the display pixels in each row to be in their selected states sequentially to apply a gradation voltages according to display data (to write display data) in synchronization with the selection timing. That is, desired image information according to display data is displayed on a display panel by the control of the orientated states of liquid crystal molecules in a liquid crystal display device, or by the control of the luminance of emission elements in an emission element type display apparatus.
If the display operation is continuously executed until the next display data has been written in the display pixels in each row, for example, during one frame period (hold type display drive control) here, then the display operation (emission operation) according to the display data continues in almost the whole of one frame period. Consequently, the display operation of a still image has a characteristic in which flickers are difficult to arise, but the display operation of a moving image has a problem in which the image information displayed in the preceding frame period is easily sighted as a residual image and the blurring and bleeding of the image information are caused to cause the deterioration of a display image quality.
Accordingly, as a display drive method of improving a display image quality by suppressing the aforementioned blurring and bleeding of a moving image in its display operation in a liquid crystal display device and an emission element type display apparatus, for example, a technique (false impulse type display drive method) is known that improves the display quality of a moving image by executing a black display operation (non-emission operation period) of setting the display pixels in each row into a non-display or low gradation display state in addition to the display operation (emission operation period) according to display data in one frame period. Such a drive control method of a display apparatus is further minutely described in, for example, Japanese Patent Application Laid-Open Publication No. 2004-264481.
If driving is performed by a relatively low frame frequency, for example, about 30 Hz by the aforesaid false impulse type display drive method, black display (non-emission) regions inserted into display (emission) regions are recognized as flickers by human visual sensation. A technique of drive at a comparatively high frame frequency of 60 Hz or more is consequently applied generally.
However, even if the frame frequency (that is, the drive frequency of a display apparatus) is set to be higher, there is a problem in which flickers and the boundaries of display regions (boundaries between emission regions and non-emission regions) are sometimes recognized when a human visual line quickly moves. Moreover, there are also the problems of causing the rise of a driver cost and the restriction of the specifications of a display panel.